The couple only made their red carpet debut together at a pre-Emmy Awards party last month, and they were first seen before that at a horse ranch in California in August.

Neither of the them have been married before, although Kaley - who was briefly engaged to addiction specialist Josh Resnik and secretly dated her 'Big Bang Theory' co-star Johnny Galecki, for two years - recently split from 'Man of Steel' actor Henry Cavill.

Speaking about their break-up, a source previously said: "She just got overwhelmed with the very public Superman relationship.